* Armenian has undergone specific sound change which is not reflected in eLinguistics.net. For this reason, its isolated position in the classification doesn't reflect the otherwise known hyptheses.
** Russian and Slovene, like all IE languages, get clearly classified into the right subfamily (Slavic) but are the only two languages which get a wrong last level sub-classification in eLinguistics.net. This is due to the very weak differenciation between the very closely related Slavic languages. Their positions within the respective sub-subfamilies have been corrected manually (difference between this tree and the raw tree).

Comments about this tree:
This tree reflects the classification of the Indo-European languages according to the data from www.eLinguistics.net. After having gathered feedbacks from the linguist community over the past three years,
the basis data of eLinguistics.net has improved. The particular challenge in this tree is to estimate dates of separations of language families. Basis data are 7000+ IE pairwise comparisons. Dates are estimated using a polynomial regression out of known relations between eLinguistics.net genetic distance and the age of common ancestors of languages (interpolation).
These results are still experimental but in many instances already in line with existing estimates and hypotheses.

For what can this be useful?
Wheareas the classification of the Indo-European languages in sub-families is not subject to debate, the place and date at which the earlier stages of the European languages are not clearly known.
There are many hypotheses, placing the Proto-Indo-European language (the common ancestor of all sub-families) between 7000 and 3500 BC. All the nodes in the tree represent a stage at which languages split from each other, forming new sub-families. Estimating the dates of theses nodes is
an interesting job, because it can be in line with hypotheses coming from other methods.
The dates in this tree are purely mathematical estimates, based on the data from eLinguistics.net.